Blood cell agglutination viewers are commonly used in medical laboratories, blood banks, and similar types of facilities. After a test tube containing a blood sample is centrifuged, a laboratory or medical technician "reads" the tube by examining the agglutination of cells in the bottom of the tube. The agglutination viewer includes a light source and a magnifying mirror to assist in this process. By positioning the sample tube between the light source and mirror, any agglutination which has occurred in the bottom of the tube can be visually detected.
In an existing type of agglutination viewer sold by Becton Dickinson and Company, the assignee of the present invention, the magnifying mirror that is used to view agglutination in the sample tube is supported by an adjustable clamp mounted on the base portion of the viewer. Ball joints allow the mirror to be adjusted to the desired orientation, and a thumb screw is used to lock the clamp in the desired position. Although this is an effective arrangement, the mechanical clamp assembly is somewhat difficult to adjust and can become worn after prolonged use.
Another disadvantage of the known agglutination viewer has to do with the nature of the illumination source, which consists of an incandescent lamp and shade assembly that is suspended over the base portion of the viewer by means of a flexible metal gooseneck. Although the flexible gooseneck is advantageous in allowing the light source to be adjusted to any desired position, the incandescent bulb and shade assembly can become hot after an extended period of operation. This is undesirable not only because of the discomfort that may be experienced by the user when adjusting the position of the light source, but also because prolonged high temperatures can lead to heat-induced failures in the lamp socket assembly. The need to provide electrical wiring in a movable part of the viewer (i.e., in the gooseneck and shade assembly), is also disadvantageous since repeated adjustment of the lamp position can cause this wiring to become broken or disconnected.
In view of the foregoing disadvantages and limitations of the prior art, it is an object of the present invention to provide an improved agglutination viewer in which adjustments in the orientation of the magnifying mirror can be carried out quickly and easily, without the need to manipulate a mechanical clamping assembly.
A further object of the invention is to provide an improved agglutination viewer in which the source of illumination does not become hot to the touch, so that it can be manipulated without discomfort even after the viewer has been in operation for an extended period of time.
A still further object of the present invention is to provide an improved agglutination viewer in which electrical wiring does not have to be provided in the portion of the illumination source which is moved or manipulated by the user, thereby avoiding problems due to wire breakage and the like.
It is a still further object of the invention to provide an improved agglutination viewer in which the illumination source is lighter in weight and more flexible than in the prior art, so that it can be adjusted more easily and accurately.